1. Field of the Invention
The present invention relates generally to seat belt warning systems for vehicles and, more specifically, to a secondary seat belt warning system for a motor vehicle.
2. Description of the Related Art
It is known that motor vehicles such as automotive vehicles often include seat belt warning systems for reminding an occupant of the vehicle that their seat belt is unbuckled. Typically, when the vehicle ignition is turned to a xe2x80x9crunxe2x80x9d or xe2x80x9conxe2x80x9d position, an audible chime and visible warning light will turn on for a predetermined amount of time to alert, or remind, the occupant to buckle or fasten their seat belt. If their seat belt is already buckled, neither the chime nor the light will turn on. The audible chime will typically only sound for a few seconds and the visible warning light will typically flash for a short period of time or remain illuminated for approximately ten to sixty seconds. After these relatively short time durations have expired, the warnings will turn off and remain off, regardless of whether the seat belt is buckled or unbuckled, until the initial ignition xe2x80x9crunxe2x80x9d position is reactivated.
An example of a seat belt usage indicating system is disclosed in U.S. Pat. No. 5,483,221 to Mutter et al. In this patent, seat belts in a motor vehicle are monitored, and a reminder is initiated in response to a belt or restraint sensor indicating an engaged or nonengaged state of a seat belt or restraint, a vehicle sensor indicating when the vehicle is in use, an annunciator controllably producing a reminder, and an electronic control controlling the annunciator. The reminder is produced when the seat restraint is in a nonengaged state after having been in an engaged state while the vehicle is in use.
It is also known to provide a secondary seat belt warning system for a motor vehicle. An example of such a system in disclosed in copending application Serial No. 09/448,352, filed Jan. 20, 2000, entitled xe2x80x9cSECONDARY SEAT BELT WARNING SYSTEMxe2x80x9d. In this application, a secondary seat belt warning system includes a control module for activating at least one output warning signal in response to receiving a plurality of predetermined control feedback input signals. The secondary seat belt warning system includes an ignition switch connected to the control module for producing an input signal to the control module indicative of a state of a vehicle ignition between an xe2x80x9coffxe2x80x9d position and an xe2x80x9conxe2x80x9d position. The secondary seat belt warning system also includes a seat belt sensor connected to the control module for producing an input signal to the control module indicative of a state of the seat belt between a buckled and unbuckled condition. The secondary seat belt warning system further includes a vehicle speed sensor connected to the control module for producing an input signal to the control module in response to the vehicle speed sensor measuring a predetermined threshold speed of the vehicle. Finally, the secondary seat belt warning system includes a seat belt indicator system connected to the control module for producing an output signal in response to the control module receiving an input signal from the seat belt sensor in the unbuckled condition and an input signal from the vehicle speed sensor above the predetermined threshold, whereby the output signal triggers at least one of an audible and visible indicator to alert the occupant of the vehicle of the unbuckled condition of the seat belt.
Although the current secondary seat belt warning system reminds the occupant to buckle their seat belt in addition to the primary warning, these secondary warnings are a xe2x80x9conce per drive cyclexe2x80x9d event typically at the start-of each trip (key cycle), and this limitation exists due to the inability to determine a seat belt user or a seat belt nonuser. Another disadvantage is that the secondary seat belt warning system does not allow the occupant to change its declaration as a seat belt user or non-user without the engine being turned off. Another disadvantage is that the secondary seat belt warning system is available only once in a drive cycle.
It is desirable to provide a secondary seat belt warning system that identifies a vehicle occupant as a seat belt user or a non-user. It is also desirable to provide a secondary seat belt warning system that combines occupant seat occupancy detection and occupant belt use monitoring to add occupant passenger seat belt reminder warnings. It is further desirable to provide a secondary seat belt warning system with repeatable warnings to warn occupants throughout the duration of a drive cycle or trip. Therefore, there is a need in the art to provide a secondary seat belt warning system that meets these desires.
Accordingly, the present invention is a secondary seat belt warning system for a. motor vehicle including at least one control module for activating at least one secondary warning signal. The secondary seat belt warning system also includes a driver seat belt sensor. for producing an input signal indicative of a state of a driver seat belt between a buckled and unbuckled condition. The secondary seat belt warning system includes at least one passenger seat belt sensor for producing an input signal indicative of a state of at least one passenger seat belt between a buckled and unbuckled condition. The at least one control module communicates with the driver seat belt sensor and the at least one passenger seat belt sensor for activating the at least one secondary warning signal to alert a corresponding occupant of the motor vehicle if the state of at least one of the driver seat belt and the at least one passenger seat belt is the unbuckled condition.
One advantage of the present invention is that a secondary seat belt warning system is provided for a motor vehicle. Another advantage of the present invention is that the secondary seat belt warning system monitors the seat belt use status of a vehicle occupant to dynamically determine if the occupant is a seat belt user or a seat belt non-user. Yet another advantage of the present invention is that a method is provided for monitoring an occupant""s seat belt and to assign them as a seat belt user or non-user and to change the assignment at any time during a drive cycle such that secondary warnings can be provided to seat belt xe2x80x9cusersxe2x80x9d at any time during a drive cycle, while not providing secondary warnings to seat belt xe2x80x9cnon-usersxe2x80x9d. Still another advantage of the present invention is that the secondary seat belt warning system provides secondary warnings whenever an occupant seat belt is unbuckled independent of when in the drive cycle it is unbuckled. A further advantage of the present invention is that the secondary seat belt warning system includes a combined driver and passenger occupant reminder feature which subtly reminds the driver and front passenger seat occupant to buckle their seat belts, in the event that they have forgotten to buckle-up at the beginning of a drive cycle. Yet a further another advantage of the present invention is that the secondary seat belt warning system includes a repeatable secondary warning feature which subtly reminds the driver and front passenger seat occupant to buckle their seat belts in the event that they have forgotten to buckle-up at any point during an extended trip or drive cycle.